During a migration image metadata from the source should be mapped to image metadata in the migration (in case any external metadata and the image ever part company!).

SO32 is a tool for extracting the metadata from the source and migration in a standard and comparable way.

To complicate things the source and migration field values may have (deliberately) changed during the migration. It may be enough to check for values in the desired fields (not everything in the source needs to have been mapped to the migration - that'll need to be configurable).
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